It is a clay of the group of the montmorillonite, characterized by its magnesian pole, the stévensite. The rock contains also silica, carbonates as well as clays of the group of the illite. Rhassoul Clay is composed of silicon, magnesium, iron, calcium, potassium, sodium, trace elements and provitamin. The Ghassoul or Moroccan Clay is a purely natural mineral product mostly composed of stevensite. It is a clayey mineral made of magnesium silicate. Optical microscope aspect:Under the optical microscope the prepared Ghassoul, Rhassoul, Rhassoul Clay or Moroccan Clay looks like a grey shapeless colloidal base on which we can see fine micelles. No trace of vegetable waste has been observed. Electron microscope aspect:The electron microscope shows that the Ghassoul, Rhassoul, Rhassoul Clay or Moroccan Clay crystalline structure is similar to the other minerals belonging to the stenvensite and the montmorillonites group. Density:The rough Ghassoul, Rhassoul, Rhassoul Clay or Moroccan Clay density is around 1.7 in the pycnometer Water content:The water content is found at 180 degrees Celsius by attaining a constant weight. The loss of weight by desiccation is nearly 13% of the total weight. Ashes content:The total ashes resulting from a complete combustion at 600 degrees Celsius, in a ceramic crucible containing the sample already dry by desiccation at 180 degrees Celsius is about 18% of the total weight.